Using the AppCache

AppCache support is deprecated. Browser vendors have deprecated AppCache so we’ve followed their lead. Remove the useAppcache attribute in the <aura:application> tag of your standalone apps (.app resources) to avoid cross-browser support issues due to deprecation by browser vendors.

If you don’t currently set useAppcache in an <aura:application> tag, you don't have to do anything as the default value of useAppcache is false.